1. Field of the Invention
The present invention relates to an electrostatic latent image developing apparatus for visualizing electrostatic latent images formed on the surface of an electrostatic latent image bearing member by an electrophotographic process.
2. Description of the Prior Art
Developing apparatus have already been provided which comprise a developing sleeve made of aluminum or the like and having a magnetic roller fixedly positioned within the sleeve, and a developer agitating roller (such as a bucket roller or screw roller) drivingly rotatable for supplying a developer to the outer periphery of the sleeve. The developing sleeve is adapted to support the developer thereon and to transport the developer to a developing station which is opposed to an electrostatic latent image bearing member and at which an electrostatic latent image formed on the surface of the bearing member is developed to a visible image.
With developing apparatus, the developing sleeve is generally accommodated in a casing shaped in conformity with the shape of the developing sleeve, with a predetermine clearance formed between the casing and the sleeve surface a disclosed, for example, in U.S. Pat. No. 3,999,514.
If the clearance is excessively large, some particles released from the mass of developer by being subjected to a mechanical stress by the agitation of the developer agitating roller or the like will spill out from the apparatus through the clearance. Conversely, if the clearance is too small, the developer clogs the clearance between the developing sleeve and the casing to overflow from the apparatus or to result in an increased torque for the rotation of the developing sleeve.
Accordingly, the clearance between the developing sleeve and the casing needs to be accurately adjusted to a value approximately equal to the height of bristles of the developer supported on the sleeve.
However, since the casing is in the form of an integral resin molding or an assembly of molded resin members which are adhered together, the casing is twisted or distorted, it is impossible to space from the sleeve by a uniform clearance and therefor has the problem of entailing spillage of the developer, clogging and an increase in the rotational torque of the sleeve.